At the itinerant stannary court which met at Lelant on 20 March 1498 two tinworks in Truthwall, While an Woth and le Neue Worke were registered. While an Woth was a relatively small sett measuring 30 perches by 20 (100m x 150m) while le Neue Worke was much bigger at 80 perches by 20 (402m x 150m) and both were described as being in “Trewothwall”. The setts were in the names of John Treskawe, John Adam, David Larens and John Mathowe.
It's now very difficult to pinpoint where these two tinworks were but they were almost certainly in ground which would have later been worked by Wheal Owles, a mine which came to occupy a very large sett extending from the coast at Wheal Edward inland as far as Tregeseal Hill. When Kalmeter visited St Just in 1724 he described active workings all the way along the tin lodes later worked by Wheal Owles, from the sea through Yield a Man Common, Wheal Drea, The Grouse Mine and Wheal Boys to what is now the B3306 between Nancherrow and Truthwall.
Later, in the mid 18th century the Usticke brothers' correspondence discussed the development of much of the same ground while in the late 18th century the ground was surveyed and mapped by Charles Moody for Elizabeth Usticke and Samuel Borlase. The locations of these early components of the Wheal Owles sett are reasonably straightforward to identify post 1724 but the 16th and 17th century details remain opaque and therefore, of course, of great interest to historians. What is pretty clear is that the Wheal Owles ground has definitely been worked since the late 15th century and almost certainly for a long period before that.
To find out more about early tinworks registrations have a look at Allen Buckley's book, The Tudor Tin Industry: The Tinners and Tinworks of Penwith and Kerrier Stannary, Penhellick Pubications, 2009.